Pulsed laser deposition of vanadium-doped manganese oxide thin films for supercapacitor applications

Thin films of vanadium-doped crystalline Mn2O3 and amorphous MnOx have been grown by the pulsed laser deposition (PLD) process on silicon wafer and stainless steel substrates at different substrate temperatures and oxygen gas pressures. It was found that V-doping level as low as 3.2 atm. % can transform the crystal structure of a crystalline Mn2O3 film into a crystalline MnO2 film. V-doping (up to 10 atm. %) has significantly lowered the specific capacitance of the crystalline Mn2O3 films. However, V-doped amorphous MnOx films did significantly increase the specific capacitance at high CV scan rate as compared with the un-doped MnOx films and the specific capacitance of V-doped amorphous films increased linearly with the V atomic percentage. At high scan rate of 100 mV s(-1), 9.7 atm. % V-doped MnOx film reached a high specific capacitance value of 95 F g(-1) indicating that V-doped amorphous MnOx is good candidate active materials for high energy supercapacitors. The results prove that elemental doping can significantly change the electrochemical properties of MnOx films. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.